The present invention relates generally to mobile communication networks, and, more particularly, to a network architecture for a mobile communication network that allows multiple telecommunications service providers to share communication resources.
Mobile communication systems typically comprise a plurality of base transceiver stations located at different antenna sites corresponding to the cells in the mobile communication system. The base transceiver stations connect to base station controllers (BSCs), which in turn connect to an mobile switching center (MSC). The MSC connects to the Public Switched Telephone Network (PSTN).
The base transceiver stations comprise a plurality of transmitters and receivers for communicating with mobile terminals within a cell. The transmitters receive digital data for transmission to the mobile terminals, encode the data, and modulate an assigned carrier frequency with the encoded data. Encoding the data for transmission may for example entail error detection or error correction coding to protect the data from errors that may occur during transmission, compression of the data to remove redundancy, and/or encryption to protect the data from eavesdroppers. The receivers located at the base transceiver stations receive signals transmitted from the mobile terminals, demodulate and decode the received signals to extract the originally transmitted information bits, and convey the information bits via a BSC to the MSC. The mobile communication system may use any one of a variety of multiple access methods, such as Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), or frequency hopping.
In present day wireless communication systems, a single manufacturer may provide the MSC, BSC, and all the equipment at the base transceiver stations to ensure compatibility between components. A single entity, such as a telecommunications service provider, typically owns all of this telecommunications equipment and charges subscribers for communication services provided using this equipment.
Antenna sites are not necessarily owned by telecommunications service providers, but instead may be rented from another party. The antenna sites frequently include structures, such as towers or buildings, on which antennas are mounted. For example, American Tower Corporation is an entity that specializes in acquiring and renting antenna sites and towers to telecommunications service providers.
Many telecommunications service providers today enter agreements that allow their subscribers to use the equipment and services of another telecommunications service provider. These agreements allow subscribers to roam outside the coverage area of their own telecommunications service provider. The standard known as the Global System for Mobile Communications (GSM) in particular has subscriber authentication provisions to enable service providers to authenticate subscribers of other service providers roaming in their coverage area. These provisions allow service providers to provide service to a roaming subscriber with confidence that a bill for the service provided can be sent to the subscriber's primary service provider and that the bill will not be disputed.
In the past, a single service provider typically owned all technical communication equipment used to provide service to subscribers. To provide for billing of services to roaming subscribers, different service providers must have compatible billing systems that facilitate cross billing another service provider for services provided to roaming subscribers. In prior art systems, a subscriber roaming in a region served by two or more service providers makes or receives calls using the equipment of either service provider, but never via both at the same time. This restriction provides a less reliable service and lower total capacity than might otherwise be achievable.